I picked up an old GMC truck that came with a 350 and carb. So I naturally slapped a junkyard 7747 on it and it's running ok.
I'm running a GM 7pin module inside a stock GM HEI. When I put a timing light on it, the timing marks are rock solid and don't move. This is with the bypass plug connected or disconnected. When I rev the engine the timing marks do go up about 5-10 degrees and that's it.
Shouldn't the timing marks advance more than a few degrees? IIRC the marks should be 'jumpy' at idle with the bypass plug connected.
Running a stock ASDU bin.
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